Loop element and noise analyzer

Abstract

There is provided a shield-structured loop element which can suppress noise via a silicon substrate and can be manufactured by a semiconductor process. The loop element includes: a first well of a first polarity that is formed on a substrate; a deep well of a second polarity that is formed below the first well; a ring-shaped second well of a second polarity that is formed on the deep well along an outer periphery of the deep well; a third well of the first polarity that is formed in an island area surrounded by the deep well and the second well; a looped conductor that is formed in a layer above the third well and has smaller outer dimensions than those of the third well; and a first path that connects the second well to a bias power supply. The second well and the deep well are electrically connected to each other.

The invention claimed is: 
     
       1. A loop element comprising:
 a first well of a first polarity that is formed on a substrate; 
 a deep well of a second polarity that is formed below the first well, the deep well being out of contact with the first well; 
 a ring-shaped second well of a second polarity that is formed on the deep well along an outer periphery of the deep well; 
 a third well of the first polarity that is formed in an area surrounded by the deep well and the second well; 
 a looped conductor that is formed in a layer above the third well; and 
 a first path that connects the second well to a bias power supply, 
 the second well and the deep well being electrically connected to each other, and 
 the bias power supply supplying a bias potential to the second well through the first path. 
 
     
     
       2. The loop element according to  claim 1 , further comprising
 a second path that electrically connects the third well to an independent ground. 
 
     
     
       3. The loop element according to  claim 1 , further comprising:
 a shield conductor that is arranged between the looped conductor and the third well, said shield conductor having a greater area than the looped conductor; and 
 a third path that electrically connects the shield conductor to an independent ground. 
 
     
     
       4. The loop element according to  claim 3 , wherein
 the third well is electrically connected to the shield conductor. 
 
     
     
       5. The loop element according to  claim 1 , further comprising
 conductors that are arranged inside and outside the looped conductor so as not to be connected with the looped conductor, 
 the conductors being arranged to have an annular opening along the looped conductor. 
 
     
     
       6. The loop element according to  claim 5 , wherein
 the conductor arranged inside the looped conductor comprises plurality of conductors such that smaller conductors are arranged closer to a center of the loop. 
 
     
     
       7. The loop element according to  claim 1 , wherein
 at least the first path and the looped conductor comprise a conductor wiring in a metal layer. 
 
     
     
       8. A noise analyzer comprising:
 the loop element according to  claim 1 ; 
 a looped conductor that is arranged independent from the loop element; 
 measurement circuits that measure voltages at terminals of the loop element and the looped conductor, respectively; and 
 an analysis circuit that performs a computation to determine a magnetic field by using a measurement of the voltage induced across the terminals of the loop element and a measurement of the voltage induced across the terminals of the looped conductor. 
 
     
     
       9. The noise analyzer according to  claim 8 , wherein
 the loop element is arranged near a noise source to be measured. 
 
     
     
       10. A semiconductor apparatus comprising the loop element according to  claim 1 . 
     
     
       11. An antenna comprising the loop element according to  claim 1 . 
     
     
       12. A communication apparatus comprising the antenna according to  claim 11 . 
     
     
       13. The loop element according to  claim 1 , wherein the looped conductor includes a loop wiring comprising a cutting portion and leads connected at respective cut ends of the cutting portion. 
     
     
       14. The loop element according to  claim 1 , wherein said deep-well is formed entirely below said first well. 
     
     
       15. The loop element according to  claim 1 , wherein said deep-well is formed entirely below said third well. 
     
     
       16. A noise analyzer comprising:
 the loop element according to  claim 1 ; 
 a looped conductor that is arranged independently from the loop element; and 
 a measurement circuit that measures voltages at terminals of the loop element and the looped conductor, respectively. 
 
     
     
       17. A noise analyzer comprising:
 the loop element according to  claim 1 ; and 
 an analysis circuit that performs a computation to determine a magnetic field by using a measurement of a voltage induced across a terminal of the loop element and a measurement of a voltage induced across a terminal of the looped conductor. 
 
     
     
       18. The loop element according to  claim 1 , wherein a conductor is arranged in a center portion of the looped conductor. 
     
     
       19. The loop element according to  claim 18 , wherein said conductor is electrically isolated from the looped conductor. 
     
     
       20. The loop element according to  claim 1 , wherein an outer dimension of the looped conductor is less than an outer dimension of the third well.